The present invention relates generally to optical devices and optical systems, and more particularly to a device for modulating a light beam intensity and a projector/exposure system using such a device.
Devices which modulate an aspect of a light beam, e.g. an amplitude or phase of the light, find a number of applications. In optical modulation applications, phase modulation is often more important than amplitude modulation. Furthermore, phase modulation devices can often perform amplitude modulation, thereby providing application flexibility. It is desired to provide a light modulation device that is fast, reliable, durable, efficient, and can be used in simple as well as complex applications.
A technical advance is provided by a new and unique light element. In one embodiment, the light element includes three electrodes, a support structure, a flexible member, and a mirror. The flexible member is connected to the support structure so that it is responsive to electrostatic forces provided by one or more of the three electrodes. The flexible member is positioned in a gap so that it can move between a first and second state, responsive to the electrostatic forces. The mirror is also attached to the flexible member, so that it too moves between a first and second state.
In another embodiment, the light element includes first, second, and third electrodes positioned adjacent to a substrate, each electrode capable of producing a force. Two support members are also connected to the substrate and a flexible member spans there between, extending over and above the three electrodes and capable of moving between a first and second state. As in the previous embodiment, a mirror is connected to and extends above the flexible member.
In another embodiment, the light element includes a first, second, and third electrode for producing a first, second and third force, respectively. A flexible member, which is responsive to a force, is connected to a support structure. A mirror is further attached to the flexible member. In operation, the flexible member, and hence the mirror, transition between different states responsive to various combinations of the first, second, and third forces.
In yet another embodiment, the light element includes two electrodes connected to the substrate for producing an electrostatic force and a flexible member suspended over the two electrodes. An actuator and a third electrode are also included, the actuator being adjacent the flexible member. The first two electrodes are situated to hold the flexible member in a prior state responsive to a hold voltage applied thereto, and the actuator is situated to selectively move the flexible member between two operational states.